Deflection-error-reduced position control apparatus for ball screw drive system
AssigneeOkuma Corporation
InventorSatoshi Eguchi
Life of this patent
Estimating the term…
Abstract
In an apparatus for controlling the position of an object driven by a servomotor via a ball screw drive system, parameters of the ball screw drive system are determined from a position command value, an acceleration command value, a torque command value and a motor speed, based on which a dynamic deflection extent while the object is driven at an adjustable speed is calculated. To compensate for this dynamic deflection extent, a deflection compensation command section calculates a deflection compensation value, a deflection speed compensation value, and a deflection torque compensation value. These compensation values are added to their related sections in the position control apparatus individually and collectively compensate for the dynamic deflection.
Claims33
A position control apparatus for controlling the position of an object, which is driven via a ball screw drive system by a servomotor, based on a predetermined command, said apparatus having a deflection compensation command section for outputting at least one of the following values:
- a deflection compensation value,
- a deflection speed compensation value, and
- a torque compensation value;
- for compensating a control error due to a possible deflection of a ball screw drive system, said at least one compensation value being calculated based on:
- a position command value,
- an acceleration command value, and
- a torque command value,
- wherein said deflection compensation command section is equipped with a compensation extent determination section including
- (a) parameter determination section having:
- 1) an integrated thrust rigidity determination section for calculating an integrated thrust rigidity of the ball screw drive system based on said position command value,
- 2) an integrated torsional rigidity determination section for calculating an integrated torsional rigidity of the ball screw drive system based on said position command value,
- 3) a load-side inertial moment determination section for calculating a current load-side inertial moment based on said acceleration command value, said torque command value the current motor speed, said integrated thrust rigidity, said integrated torsional rigidity and a load-side inertial moment in previous cycle;
- (b) a first amplifier for multiplying said acceleration command value by a reciprocal number of said integrated thrust rigidity calculated by said parameter determination section;
- (c) a second amplifier for multiplying said acceleration command value by a reciprocal number of said integrated torsional rigidity calculated by said parameter determination section;
- (d) an adder for obtaining a combined output of said first and second amplifiers;
- and
- (e) a third amplifier for calculating a deflection extent by multiplying the output of said adder by said load-side inertial moment calculated by said parameter determination section.
A semi-closed position control apparatus for controlling the position of an object, which is driven via a ball screw drive system by a servomotor, by feedbacking based on a position command value representing the position of the object and by substituting a feed position of the servomotor for the position of the object as a position feedback, said apparatus comprising:
- (a) a speed command value calculation section for calculating a speed command value by differentiating the position command value;
- (b) an acceleration command value calculation section for calculating an acceleration command value by differentiating said speed command value;
- (c) a torque command value calculation section for calculating a torque command value, which is a position command value of the servomotor;
- (d) a motor speed calculation section for calculating a motor speed based on the feed position of the servomotor;
- (e) a deflection compensation command section for outputting a deflection compensation value, a deflection speed compensation value and a deflection torque compensation value to compensate a control error due to a possible deflection of the ball screw drive system, which deflection occurred when the object is driven an adjustable speed, based on said position command value, said acceleration command value, said torque command value and the motor speed;
- (f) a position deviation calculation section for calculating a position deviation based on said position command value, said deflection compensation value and said position feedback;
- (g) a speed deviation calculation section for calculating a speed deviation based on a value obtained by multiplying said position deviation by a predetermined constant, said speed command value, said deflection speed compensation value and a speed feedback obtained by differentiating said position feedback;
- and
- (h) wherein the torque command value calculation section calculates a torque command value based on a value obtained by proportioning and integrating said speed deviation, a value obtained by multiplying said speed command value by a predetermined constant and said deflection compensation value.
A full-closed position control apparatus for controlling the position of an object, which is driven via a ball screw drive system by a servomotor, by feedbacking based on a position command value representing the position of the object and by employing a real position of the object as a position feedback, said apparatus comprising:
- (a) a speed command value calculation section for calculating a speed command value by differentiating the position command value;
- (b) an acceleration command value calculation section for calculating an acceleration command value by differentiating said speed command value;
- (c) a torque command value calculation section for calculating a torque command value, which is a position command value of the servomotor;
- (d) a motor speed calculation section for calculating a motor speed based on the feed position of the servomotor;
- (e) a deflection compensation command section for outputting a deflection speed compensation value and a deflection torque compensation value to compensate a control error due to a possible deflection of the ball screw drive system, based on said position command value, said acceleration command value, said torque command value and the motor speed;
- (f) a position deviation calculation section for calculating a position deviation based on said position command value and said position feedback;
- (g) a speed deviation calculation section for calculating a speed deviation based on a value obtained by multiplying said position deviation by a predetermined constant, said speed command value, said deflection speed compensation value and a speed feedback obtained by differentiating said position feedback;
- (h) wherein the torque command value calculation section calculates a torque command value based on a value obtained by proportioning and integrating said speed command value by a predetermined constant and said deflection compensation value.
A full-closed position control apparatus for controlling the position of an object, which is driven via a ball screw drive system by a servomotor, by feedbacking based on a position command value representing the position of the object and by employing as a position feedback a value based on both a real position of the object and a feed position of the servomotor, said apparatus comprising:
- (a) a speed command value calculation section for calculating a speed command value by differentiating the position command value;
- (b) an acceleration command value calculation section for calculating an acceleration command value by differentiating said speed command value;
- (c) a torque command value calculation section for calculating a torque command value, which is a position command value of the servomotor;
- (d) a motor speed calculation section for calculating a motor speed based on the feed position of the servomotor;
- (e) a deflection compensation command section for outputting a deflection compensation value, a deflection speed compensation value and a deflection torque compensation value to compensate a control error due to a possible deflection of the ball screw drive system based on said position command value, said acceleration command value, said torque command value and the motor speed;
- (f) a position deviation calculation section for calculating a position deviation based on said position command value, said deflection compensation value and said position feedback;
- (g) a speed deviation calculation section for calculating a speed deviation, based on a value obtained by multiplying said position deviation by a predetermined constant, said speed command value, said deflection speed compensation value and a speed feedback obtained by differentiating said position feedback;
- (h) wherein the torque command value calculation section calculates a torque command value based on a value obtained by proportioning and integrating said speed deviation, a value obtained by multiplying said speed command value by a predetermined constant and said deflection compensation value.
A position control apparatus for controlling the position of an object, which is driven via a ball screw drive system by a servomotor, based on a predetermined command, said apparatus having a deflection compensation command section for outputting at least one of:
- a deflection position compensation value,
- a deflection speed compensation value, and
- a deflection torque compensation value;
- for compensation a control error due to a possible deflection of the ball screw drive system, said at least one compensation value being calculated based on at least one of:
- a position command value,
- an acceleration command value,
- a speed command value, and
- a torque command value, wherein said deflection compensation command section is equipped with a compensation extent determination section including a parameter determination section having at least one of:
- 1) an integrated thrust rigidity determination section for calculating an integrated thrust rigidity of the ball screw drive system based on said position command value, and for multiplying said acceleration command value by a reciprocal number of said integrated thrust rigidity;
- and
- 2) an integrated torsional rigidity determination section for calculating an integrated torsional rigidity of the ball screw drive system based on said position command value, and for multiplying said acceleration command value by a reciprocal number of said integrated thrust rigidity.
A semi-closed position control apparatus for controlling the position of an object, which is driven vial a ball screw drive system by a servomotor, by feedbacking based on a position command value representing the position of the object and by substituting a feed position of the servomotor for the position of the object as a position feedback, said apparatus comprising:
- 1) at least one of:
- (a) a speed command value calculation section for calculating a speed command value by differentiating the position command value,
- (b) an acceleration command value calculations section for calculating an acceleration command value by differentiating said speed command value,
- (c) a torque command value acceleration calculation section for calculating a torque command value, which is a position command value of the servomotor, and
- (d) a motor speed calculation section for calculating a motor speed based on the feed position of the servomotor;
- 2) a deflection compensation command section for outputting at least one of a deflection compensation value, a deflection speed compensation value and a deflection torque compensation value to compensate a control error due to a possible deflection of the ball screw drive system, based on at least one of said position command value, said acceleration command value, said torque command value and the motor speed;
- 3) a position deviation calculation section for calculating a position deviation based on said position command value, said deflection compensation value and said position feedback;
- and
- 4) a speed deviation calculation section for calculating a speed deviation, based on at least one of a value obtained by multiplying said position deviation by a predetermined constant, said speed command value, said deflection speed compensation value and a speed feedback obtained by differentiating said position feedback;
- wherein the torque command value calculation section calculates a torque command value based on at least one of a value obtained by proportioning and integrating said speed deviation, a value obtained by multiplying said speed command value by a predetermined constant and said deflection compensation value.
A full-closed position control apparatus for controlling the position of an object, which is driven via a ball screw drive system by a servomotor, by feedback based on a position command value representing the position of the object and by employing a real position of the object as a position feedback, said apparatus comprising:
- 1) at least on of:
- (a) a speed command value calculation section for calculating a speed command value by differentiating the position command value,
- (b) an acceleration command value calculation section for calculating an acceleration command value by differentiating said speed command value,
- (c) a torque command value calculating section for calculating a torque command value, which is a position command value of the servomotor, and
- (d) a motor speed calculation section for calculating a motor speed based on the feed position of the servomotor;
- 2) a deflection compensation command section for outputting at least one of a deflection compensation value, a deflection speed compensation value and a deflection torque compensation value to compensate a control error due to a possible deflection of the ball screw drive system, based on at least one of said position command value, said acceleration command value, said torque command value and the motor speed;
- 3) a position deviation calculation a position deviation based on said position command value, said deflection compensation value and said position feedback;
- and
- 4) a speed deviation calculation section for calculating a speed deviation, based on at least one of a value obtained by multiplying said position deviation by a predetermined constant, said speed command value, said deflection speed compensation value and a speed feedback obtained by differentiating said position feedback;
- wherein the torque command value calculation section calculates a torque command value based on at least one of a value obtained by proportioning and integrating said speed command deviation, a value obtained by multiplying said speed value by a predetermined constant and said deflection compensation value.
A full-closed position control apparatus for controlling the position of an object, which is driven via a ball screw drive system by a servomotor, by feedbacking based on a position command value representing the position of the object and by employing as a position feedback a value based on both a real position of the object and a feed position of the servomotor, said apparatus comprising:
- 1) at least one of:
- (a) a speed command value calculation section for calculating a speed command value by differentiating the position command value,
- (b) an acceleration command value calculation section for calculating an acceleration command value by differentiating said speed command value,
- (c) a torque command value calculation section for calculating a torque command value, which is a position command value of the servomotor, and
- (d) a motor speed calculation section for calculating a motor speed based on the feed position of the servomotor;
- 2) a deflection compensation command section for outputting at least one of a deflection compensation value, a deflection speed compensation value and a deflection torque compensation value to compensate a control error due to a possible deflection of the ball screw drive system, based on at least one of said position command value, said acceleration command value, said torque command value and the motor speed;
- 3) a position deviation calculation section for calculating a position deviation based on said position command value, said deflection compensation value and said position feedback;
- and
- 4) a speed deviation calculating section for calculating a speed deviation, based on at least one of a value obtained by multiplying said position deviation by a predetermined constant, said speed command value, said deflection speed compensation value and a speed feedback obtained by differentiating said position feedback;
- wherein the torque command value calculation section calculates a torque command value based on at least one of a value obtained by proportioning and integrating said speed deviation, a value obtained by multiplying said speed command value by a predetermined constant and said deflection compensation value.
Dependencies are inferred from the claim text.